Browsing by Author "Chiu, SY"

Now showing 1 - 12 of 12

A study on electrochemical metrologies for evaluating the removal selectivity of AlCMP
(1999)
Chiu, SY
;
Hsu, JW
;
Tung, IC
;
Shih, HC
;
Feng, MS
The in-situ electrochemical measurements were performed for the Al and Ti disks in the various slurries under the polishing or static condition. The slurries used contained Al2O3 abrasive, phosphoric acid, citric acid and hydrogen peroxide. The results showed that the addition of H2O2 could help to form an effective passivating layer on the Al surface. Besides, the addition of H2O2 enhanced Al dissolution. The maximum corrosion potential drop between the abraded and non-abraded Al electrodes corresponded to the possible maximum polishing rate of Al. The novel equipment for in-situ galvanic measurements was designed for evaluating the Al/Ti galvanic couple. It was found that Al dissolution could be suppressed in the slurry with the addition of 6 vol% H2O2 at pH 4. As regards the Al/Ti removal selectivity, the polishing with the addition of 6 vol% H2O2 at pH 4 would mitigate the Al dishing, since the polishing and dissolution of Al could be suppressed while those of Ti could be enhanced.
Aplication of plasma immersion ion implantation on seeding copper electroplating for multilevel interconnection
(2005-05-01)
Chiu, SY
;
Wang, YL
;
Chang, SC
;
Feng, MS
;
材料科學與工程學系
In this study, an effective seeding technology, plasma immersion ion implantation of palladium (PIII Pd), was proposed to achieve defect-free gap filling for copper electroplating (Cu-ECP). It was found that a threshold dosage (similar to 5.2 x 10(18) m(-2)) of PIII I'd was required to drive Cu-ECP and the dependence of Pd dosage on the implantation time was quasi-linear. The thickness of electroplated copper films increased as the Pd dosage increased. Too high a Pd dosage caused a rough copper film with high resistivity (> 10 mu Omega cm) while too low a I'd dosage resulted in an insufficient nucleation site for Cu-ECP, leading to poor film adhesion. In addition, a higher substrate bias of PIII was suggested to enhance the gap-filling capability of Cu-ECP and the Cu(111) formation of electroplated copper films. (c) 2004 Elsevier B.V. All rights reserved.
Characterization of additive systems for damascene Cu electroplating by the superfilling profile monitor
(2000-11-01)
Chiu, SY
;
Shieh, JM
;
Chang, SC
;
Lin, KC
;
Dai, BT
Gap-filling dynamics of several different species of additives for copper electrodeposition was investigated by monitoring the cross section of a partially filled copper profile on the scanning electron microscopy photo. The filling ration Deltay/Deltax between "bottom-up" with "sidewall shift" was found to be proportional to the filing power of additives. The adsorption-diffusion model combined with cathode polarization and cyclic voltammetric stripping measurements was employed to explain the attribution of additives in superfilling phenomena. The superfilling dynamics was achieved under behavior of additives providing selective inhibition gradient within the damascene feature. By means of those analyses, we have optimized the appropriate amount of additives and achieved the superfilling performance for 0.15 mum vias with aspect ratio 6 by an acid-copper electrolyte with polyethylene glycol, Cl-, and 2-mercaptopyridine (2-MP). Due to the additive of 2-MP, chelate formed which enhanced adsorption ability on Cu-0 surface, and the concentration gradient between side-wall shift and bottom-up in the damascene became high enough to attend superfilling electroplating. (C) 2000 American Vacuum Society. [S0734-211X(00)13506-1].
Electrochemical behavior of copper chemical mechanical polishing in KIO3 slurry
(2002-03-01)
Hsu, JW
;
Chiu, SY
;
Tsai, MS
;
Dai, BT
;
Feng, MS
The electrochemical behavior of polishing copper with colloidal silica abrasive slurry formulated with KIO3 oxidizer has been investigated. For planarization of the surface morphology, the control of the surface passivation of Cu is critical during polishing. KIO3 is not only all oxidizer but also a passivator for copper in an acidic slurry by forming a CuI layer on the surface. With alkaline slurry, Cu2O is the primary corrosion product on the Cu surface. The copper corrosion rate and removal rate can be decreased dramatically with increasing slurry pH. The low corrosion resistance or high corrosion susceptibility of Cu as determined by electrochemical measurements is the basis for the high removal rates. The copper removal rate is reduced from 4600 to 650 Angstrom/min when the slurry pH is increased from 2 to 5: and the copper removal rate levels off atpH 7 with a steady-state removal rate of 200 Angstrom/min, (C) 2002 American Vacuum Society.
High-selectivity damascene chemical mechanical polishing
(2006-03-01)
Chiu, SY
;
Wang, YL
;
Liu, CP
;
Chang, SC
;
Hwang, GJ
In this study, multi-step chemical mechanical polishing (CMP) with different copper removal rates and polishing pads is used to eliminate topography efficiently and to reduce micro-scratches on copper films. In colloidal-silica-based slurry, the polishing behaviors of copper, tantalum and silicon dioxide are found to relate to that kind of alkaline additives. The size of cations from alkaline additives influences the zeta potential of slurries, so as to vary the material removal rate. The addition of small-sized K+ from KOH provides high removal selectivity of tantalum/copper and oxide/copper, so as to benefit the reduction of copper dishing. (c) 2005 Elsevier B.V All rights reserved.
Nitric acid-based slurry with citric acid as an inhibitor for copper chemical mechanical polishing
(1999-10-15)
Hu, TC
;
Chiu, SY
;
Dai, BT
;
Tsai, MS
;
Tung, IC
A novel inhibitor, citric acid, was introduced in the HNO3-based slurry for copper chemical mechanical polishing. It was anticipated that a passivation layer could be formed on the copper surface in the presence of citric acid. In a 3 vol.% HNO3 solution, the passivation effect derived from citric acid saturated as the citric acid concentration reached ca. 0.01 M. The polishing rate was found to decrease with the addition of citric acid. The results showed that the HNO3-based slurry with citric acid as an inhibitor could achieve good surface planarity for copper chemical mechanical polishing. (C) 1999 Published by Elsevier Science S.A. All rights reserved.
Providing mobile LAN access capability for bluetooth devices
(2002)
Chiu, SY
;
Chang, HP
;
Chang, RC
;
資訊工程學系
;
Department of Computer Science
In this paper, we design and implement a Bluetooth system with mobile LAN access capability. First, by adding a virtual network interface card (NIC) driver between IP and Bluetooth protocol stack, Bluetooth users can use their Bluetooth devices to access the LAN resources via the Bluetooth access points. Besides, to accommodate with the mobility characteristics in Bluetooth network, we also propose a new handoff scheme. Instead of passively waiting for a handoff indication by the expiration of link supervision timer, in this paper, we detect a handoff actively and promptly by measuring the RSSI (Receive Signal Strength Indication) value. In addition, our proposed handoff scheme eliminates the inquiry procedure and only requires paging procedure during a handoff. We have implemented a prototype of Bluetooth system with mobile LAN access capability by our proposed scheme. Experimented results show that the handoff duration is significant reduced than the normal scheme.
Study the impact of liner thickness on the 0.18 mu m devices using low dielectric constant hydrogen silsesquioxane as the interlayer dielectric
(2000-12-01)
Lan, JK
;
Wang, YL
;
Wu, YL
;
Liou, HC
;
Wang, JK
The electrical performance of hydrogen silsesquioxane (HSQ) as the interlayer level dielectric (ILD) has been determined by using two-metal-layered test structures to study the impact of oxide liner thickness on the capacitance reduction. In comparison with SiO2, HSQ test structures formed with SiO2 cap and liner or with SiO2 cap only, have 20-27% lower intraline capacitance while 6-16% reduction was observed for fluorosilicate glass (FSG) relative to SiO2. It was found that the capacitance of SiO2/HSQ ILDs did not vary with oxide liner thickness as expected. Similar effects were observed with via resistance measurement. Analysis of the structure shows that wide variation of SiO2/HSQ/SiO2 stack thickness after oxide Chemical Mechanical Polishing (CMP) step changed the expected contribution of liner thickness on the intraline and interlayer capacitance. This thickness variation also has a strong impact on landed/unlanded via resistance. Therefore, a good control of oxide CMP on the ILD stack is needed to reduce the thickness variation of the liner/HSQ/cap ILD stack which in turn will enhance process yields in the 0.18 mum devices. (C) 2000 Elsevier Science B.V. All rights reserved.
Temperature-dependent transport properties of n(+) GaAs/low-temperature GaAs/n(+) GaAs structures grown by molecular beam epitaxy
(1996-06-01)
Chen, JF
;
Chen, NC
;
Chiu, SY
;
Wang, PY
;
Lee, WI
The temperature-dependent I-V characteristics of n(+) GaAs low-temperature GaAs(AlGaAs) n(+) GaAs structures in which the low-temperature layers were grown at 250, 350, and 450 degrees C were analyzed. Band conduction with an activation energy of 0.72 eV dominates at T>250 K. Hopping conduction dominates at T<250 K, where the resistivity was found to be insensitive to temperature. From this analysis, it is shown that Fermi level is pinned to an acceptorlike deep level of about 10(17) cm(-3), which lies at 0.72 eV below the conduction band. Measured capacitance can be described in terms of a parallel-plate capacitance with separation being equal to the expected growth thickness. Majority traps (electrons) were observed by deep-level transient spectroscopy with an activation energy about 0.72 eV, confirming the result of the resistivity analysis. In addition, the I-V characteristics were fitted to the simulated curves based on a simplified space-charge limited theory and the result was found to be consistent with the resistivity analysis. (C) 1996 American Institute of Physics.
Temperature-dependent transport properties of n(+) GaAs/low-temperature GaAs/n(+) GaAs structures grown by molecular beam epitaxy
(1996-06-01)
Chen, JF
;
Chen, NC
;
Chiu, SY
;
Wang, PY
;
Lee, WI
The temperature-dependent I-V characteristics of n(+) GaAs low-temperature GaAs(AlGaAs) n(+) GaAs structures in which the low-temperature layers were grown at 250, 350, and 450 degrees C were analyzed. Band conduction with an activation energy of 0.72 eV dominates at T>250 K. Hopping conduction dominates at T<250 K, where the resistivity was found to be insensitive to temperature. From this analysis, it is shown that Fermi level is pinned to an acceptorlike deep level of about 10(17) cm(-3), which lies at 0.72 eV below the conduction band. Measured capacitance can be described in terms of a parallel-plate capacitance with separation being equal to the expected growth thickness. Majority traps (electrons) were observed by deep-level transient spectroscopy with an activation energy about 0.72 eV, confirming the result of the resistivity analysis. In addition, the I-V characteristics were fitted to the simulated curves based on a simplified space-charge limited theory and the result was found to be consistent with the resistivity analysis. (C) 1996 American Institute of Physics.
The application of electrochemical metrologies for investigating chemical mechanical polishing of Al with a Ti barrier layer
(2003-11-15)
Chiu, SY
;
Wang, YL
;
Liu, CP
;
Lan, JK
;
Ay, C
In situ electrochemical measurements were performed for Al and Ti disks in various slurries during polishing and static conditions. The electrochemical results obtained from the corrosion potential drop of Al polishing have verified that the maximum removal rate of metal CMP can be achieved when the removal rate of the surface oxide was equal to its growth rate. However, Ti polishing did not exist maximum removal rate. The effects of H2O2%, pH values and pressure on the Al and Ti polishing behaviors were explored by using potentiodynamic scan. The corrosion potential drop was found to be a good index for polishing removal rate. The corrosion potential drop changed with increasing H2O2% for Al polishing and there existed a maximum value. But the corrosion potential drop increased with increasing H2O2% for Ti polishing. The pH value had different effects on Al and Ti polishing. Higher pH values gave higher Al removal rate but lower Ti removal rate. The Al polishing showed more pressure sensitive than Ti polishing did. The galvanic current was measured for AIM polishing. For slurry with 6 vol.% H2O2 and pH = 4, the abraded Al electrode obtained a negative current, which implied Ti oxidation was enhanced. (C) 2003 Elsevier B.V. All rights reserved.
The removal selectivity of titanium and aluminum in chemical mechanical planarization
(2002-03-01)
Hsu, JW
;
Chiu, SY
;
Wang, YL
;
Dai, BT
;
Tsai, MS
The removal selectivity control of aluminum and titanium metal barrier during aluminum chemical mechanical polishing in the Damascene process is known to be critical for surface planarity without metal dishing and dielectric erosion. Unfortunately, the electrochemical behaviors of aluminum and titanium are dissimilar, as one may expect. In this study, in situ electrochemical impedance spectroscopy was carried out to investigate the influences of H(2)O(2) concentration, slurry pH, and metal oxide formation through the passivation on aluminum and titanium. As H(2)O(2) concentration increases, the measured impedance of aluminum and titanium decreases, or the oxidation rates of these two metals are enhanced upon increasing the oxidizer concentration. As the slurry pH increases, the removal rate of polished titanium increases, but it decreases for polished aluminum. The removal rate of titanium was limited to its oxidation rate and aluminum was limited to its oxide dissolution rate. (C) 2002 The Electrochemical Society.